GP2 - Birmingham Workshop Program: Topological Superconductivity in Altermagnetic Heterostructures on a Honeycomb Lattice

Session Information

Location: Physics West 103 | School of Physics and Astronomy, University of Birmingham
Day: 1. Tuesday 21st April
Time: 17:00-18:00
Chairperson: N/A

Presentation Details

Presentation Type: Poster | 
Title: Topological Superconductivity in Altermagnetic Heterostructures on a Honeycomb Lattice
Abstract: The realisation of topological superconductivity is an ongoing endeavour. A common approach makes use of semiconductor-superconductor heterostructures. However, the requirement of an external magnetic field complicates experimental implementations due to the energy scales involved. Recently, an alternative proposal suggested replacing the semiconductor with an altermagnet [1]. Altermagnets exhibit net zero magnetisation whilst still breaking time-reversal symmetry [2], removing the need for an external field.

We consider such a heterostructure on a honeycomb lattice and demonstrate that the phase diagram becomes more complex than that of models on a square lattice. By calculating the Chern number we characterise the phases for a range of parameters. We find topological regimes that host protected Majorana edge modes and subsequently confirm their robustness to various disorder configurations. Additionally, we identify parameter regimes that exhibit higher-order topology through the appearance of zero-energy Majorana corner modes. While these modes hold promise in potential implementations of topological quantum computation, we show that their detection may inhibited by the presence of vacancies which result in other low energy states. Therefore, any potential observation of the corner modes will be sensitive to the microscopic details of the system.

[1]. S. A. A. Ghorashi, T. L. Hughes, J. Cano. Phys. Rev. Lett. 133, 106601 (2024).
[2]. L. Šmejkal, J. Sinova, and T. Jungwirth. Phys. Rev. X 12, 040501 (2022).
[3]. G. McArdle, B. Kiraly, P. Wadley, A. Gammon-Smith. arXiv:2601.05662 (2026).

Presenter

Dr George McArdle
University of Nottingham | United Kingdom

Authors

1. McArdle, George | School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
2. Kiraly, Brian | School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
3. Wadley, Peter | School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
4. Gammon-Smith, Adam | School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK